In the related art, an electric outboard motor using an electric motor as a power source has been known.
For example, as shown in FIG. 3, an electric outboard motor 100 having an upper unit 101, a middle unit 102 and a lower unit 103 and configured to be dividable into three pieces is disclosed (refer to Patent Document 1). The middle unit 102 has a lower mount 112 provided at a lower part of a middle case 110, an upper mount 113 provided in a mount case 111 positioned at an upper part of the middle case 110, an electric motor 114 covered by a motor cover 115, and a bracket device 116 attached to a hull 200. The bracket device 116 has a swivel unit 117 (steering shaft) configured to rotatably support front end portions of the respective mounts 112, 113 and a tilt shaft 118 arranged in front of an upper end of the swivel unit 117. The lower unit 103 has a lower case 120 functioning as a rudder, and a propeller shaft 122 configured to transmit an output of the electric motor 114 to a propeller 123 via a drive shaft 121.
The middle unit 102 is provided with a gear deceleration device 130 configured by a drive gear 131 and a driven gear 132. The driven gear 132 is arranged in front of the drive gear 131. An output shaft of the electric motor 114 is coupled to the drive gear 131, and an upper end portion of the drive shaft 121 is coupled to the driven gear 132. In the meantime, the drive shaft 121 extends downwards to couple a lower end portion thereof to the propeller shaft 122.
The lower mount 112 is arranged below the driven gear 132 and the swivel unit 117 is arranged at the front of the driven gear 132. That is, the gear deceleration device 130, the electric motor 114 and the drive shaft 121 are offset rearwards with respect to the swivel unit 117 so as to avoid interference with the swivel unit 117. The electric outboard motor 100 (swivel unit 117) is configured to rotate (tilt up/down) in an upward and downward direction about the tilt shaft 118 serving as a support point.    Patent Document 1: Japanese Patent Application Publication No. 2005-162055A
However, the technology disclosed in Patent Document 1 has a problem that the middle unit 102 is enlarged because the electric motor 114, the drive shaft 121 and the like are offset rearwards so as to avoid the swivel unit 117. Also, the technology disclosed in Patent Document 1 has a problem that the number of components and a weight increase because the useless components such as the motor cover 115 and the mount case 111 are provided.
Also, according to the technology of Patent Document 1, since the lower case 120 functioning as a rudder is offset rearwards with respect to the swivel unit 117, it is difficult to shorten an interval D1 (offset amount) between a center C of a lateral rudder force (lift force of the rudder) acting on the lower case 120 and a shaft center of the swivel unit 117. For this reason, the technology of Patent Document 1 has a problem that a large force is required to operate the rudder. Further, the technology of Patent Document 1 has a problem that a large force is required to tilt up the electric outboard motor 100 because an interval D2 between a shaft center of the electric motor 114, which is a heavy object, and the shaft center of the swivel unit 117 increases.